Method of and apparatus for checking the tightness of a watchcase



METHOD OF AND AiPARATUS FOR CHECKING THE TIGHTNESS 0k A WATCHCASE Filed May 1, 1968 June 30, 1970 I E MORF 3,517,547

United States Patent 3,517,547 METHOD OF AND APPARATUS FOR CHECKING THE TIGHTNESS OF A WATCHCASE Ernest Morf, Domaine de Vaudijon, Colombier, N euchatel, Switzerland Filed May 1, 1968, Ser. No. 725,832 Claims priority, application Switzerland, May 31, 1967, 7 ,694/ 67 Int. Cl. G01m 3/06, 3/32 US. Cl. 73-455 4 Claims ABSTRACT OF THE DISCLOSURE The tightness of a watchcase is checked firstly by increasing the air pressure therewithin. Therefore, an additional amount of air is blown through the stem tube into the watchcase by means of a pump. If the overpressure thus created in the watch visibly stands, the watchcase is then immersed into a liquid exposed to the atmospheric pressure and having a low viscosity. The immersion is carried out while maintaining the overpressure in the :watch. If the tightening means of the watch have some defect, air bubbles can immediately be observed in the liquid.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to checking the tightness of watchcases, in particular to the methods and apparatus operating by immersing the watchcase into a liquid submitted to a pressure lower than that in their inner space.

Description of the prior art Checking the tight closure of a watchcase by immersing the same into a liquid constitutes a process wellknoWn to those skilled in the art. It has the advantage to reveal the smallest failure quickly and upon a mere observation. Due to the difference of pressures in the watchcase and in the immersing liquid the air contained in the former escapes as soon as the watchcase is not perfectly tightly closed and forms bubbles which are easily and immediately noticeable in the liquids. Moreover, these bubbles give a full information about the place (or places) Where the tightening means are defective.

The known methods and the apparatus used for performing the same have, however, several drawbacks. The watchmaker, who has to deliver a watch to a customer either on selling the same or after a repair or a service, can, for instance, not resort to these methods without exposing the watch to a great injury. Immersing a watch into a liquid would, indeed, cause great damages if the tightening means of its casing had a heavy failure, because the immersing liquid would then reach the watch movement even if the watch were removed from the liquid as soon as the failure had been noticed. In such an event the watch movement would have to be disassembled and each part thereof to be thoroughly cleaned. Some parts would perhaps even have to be replaced.

Another drawback of the known apparatus is due to the requirement of producing with them the pressure difference between the watchcase inner space and the immersing liquid by reducing the pressure of the latter below the atmospheric pressure. To obtain this result the known apparatus must include a perfectly tight container having a volume large enough in order to receive a watch. Moreover, if it is not intended to immerse the Watch before having reduced the pressure within the container and being thus ready to observe the bubbles, the volume of this container must even be so large as to comprise, on the one hand, a free portion, and, on the other hand, a portion filled with the immersing liquid, each portion being capable of receiving the watch. Control means operable from outside the container have additionally to be provided for moving the Watch within the container from one portion to the other one thereof after having reduced the inner pressure of the container. 'Finally, the pressure within the container can only be reduced to the required extent with the help of important, cumbersome and expensive means.

The known apparatus for checking the tightness of a watchcase by immersing the watch into a liquid are consequently inadequate for most of the watchmakers who are in direct contact with the customers.

In order to avoid the risk of immersing the watch movement in the event of a heavy failure of the tightening means of the watchcase, a slightly different checking method has been imagined and apparatus have been constructed in order to carry out that method. According to that second known method a failure of the tightening means is no longer revealed by observing a flow from the inner space of the watchcase toward the outside thereof, but by observing a flow in the reverse direction. With this second method, the Watch need no longer be immersed into a liquid; it is a. gaseous fluid which enters the watchcase if its tightening means are defective. The checking operation accordingly comprises the step of increasing the pressure within a container of the checking apparatus above the atmopsheric pressure. Since the gas flow entering the watchcase is not visible like the bubbles of the first known method mentioned hereabove, instruments have to assist the operator. With the known apparatus an incidental gas fiow is detected by measuring either the volume of the gas which leaves the container of the apparatus and enters the watchcase or the deformation of the watch glass which, after having been urged toward the interior of the casing by the overpressure produced outside the same, progressively returns into its natural position if a failure of the tightening means of the watchcase permits the pressure inside and that outside to balance each other or, finally, the radioactivity of the gas which enters the watchcase. All these known measuring instruments are obviously delicate and very expensive. They have to be handled by a highly qualified stafi. Moreover, measuring the gas flow which enters the watchcase takes a relative long period of time so that the existing apparatus for carrying out the second known method are too expensive not only for the watchmakers being in direct contact with the customers, but even for the 'watch manufacturers, because of the very poor output of these known apparatus.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide an improved method, which enables checking the tightness of a watchcase by simple means and at low cost, which can easily and quickly be carried out by every vvatchmaker, while ensuring a full guarantee of the safety of the checking operation as well as of that of the watch movement.

A more specific object of the invention consists in a method comprising the steps of first producing within the watchcase, while the same is exposed to the atmosphere, an air pressure which exceeds the atmospheric pressure through a continuously observable amount, and then immersing the watchcase into a liquid exposed to the atmosphere pressure, while retaining the overpressure previously produced within the watchcase.

The overpressure produced within the watchcase before immersing the same visibly decreases as soon as the tightening means of this watchcase are strongly defective. That visible pressure decrease thus immediately informs the operator and avoids a liquid infiltration in the watch movement. Due to its first step the method according to the invention has all the advantages, but not the drawbacks of the first group of known methods mentioned above. Carrying out the method according to the invention does obviously not require anyone of the delicate and intricate measuring operations of the second known method.

Another object of the invention is to create a simple apparatus for checking the tightness of a watchcase.

A more particular object of the invention consists in an apparatus comprising a pump having a piston permanently standing under the action of spring means, and a nozzle provided with a bore, the diameter of which is exactly adjusted to the nominal diameter of the watchcase tube.

Still further objects of the invention will become apparent in the course of the following description.

BRIEF DESCRIPTION OF THE DRAWING One embodiment of the apparatus according to the invention is represented diagrammatically and by Way of example in the annexed drawing which also illustrates, by Way of example, how the method according to the invention can be carried out.

In the drawing:

FIG. 1 is an elevational and part sectional view of the apparatus illustrating a first step of the method according to the invention;

FIG. 2 is a side view of the apparatus of FIG. 1;

FIG. 3 is a view similar to that of FIG. 2 illustrating a second step of the method according to the invention, and

FIG. 4 is a cross-section on a larger scale of a part of the apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT To carry out the second step of the method according to the invention the apparatus represented in the drawing substantially comprises a flat and elongated container I intended for operating in two different work ing positions. In the first working position the container 1 is standing as shown in FIGS. 1 and 2. The second working position is shown in FIG. 3 in which the container is lying. An upper front section of the container is cutout thus constituting a pair of rectangular crossed cups 1a and 1b.

Container 1 is filled with a liquid 2 which can be water or preferably a liquid having less viscosity than water, such as, for instance, a mixture of water and alcohol comprising 30 to 50% of alcohol. The liquid could even consist of pure alcohol. When container 1 is standing, liquid 2 fills cup 1a as shown in FIG. 2. In that working position the liquid 2 reaches a grid 3 secured to the wall of container 1. Grid 3 prevents the watch from incidentally falling into cup 1a, for instance, as a consequence of an unlucky handling. When container 1 is lying, liquid 2 fills cup 1b as shown in FIG. 3.

The watch 4, which is to be checked, is located in cup 1b. It is held in place by a perforated spring blade 5 bearing on two pins 6 set in the backwall of container 1. The length of blade 5 is chosen in such manner that, at rest, its two ends abut against the side walls of container 1. A plurality of pairs of pins -6 can be provided so that blade 5 may hold watches of dilferent sizes ranging from the smallest ladies watches to the largest wristwatches for men.

In order to carry out the first step of the method according to the invention the apparatus represented in the drawing still comprises a pump secured to the upper wall of container 1. That pump comprises a cylinder 7, a piston 8 which can be actuated by means of a control button 9, a pushing spring 10 and a conduit 11 entering cup 1b. As shown in detail in FIG. 4, a nozzle 12 is set on the end of conduit 11 which is provided with a side branch constituted by a bore 13 provided in its side wall.

Nozzle 12 is removable. It is preferably made out of a relatively hard plastic, such as nylon. Nozzle 12 is. moreover, provided with a bore 14 exactly adjusted to the nominal diameter of tube 15 of the casing of watch 4, which serves as passage for the winding and hand-setting stem (not shown). Bore 14 is adapted to tube 15 in such manner that if the latter is intact, nozzle 12 will match thereon under exactly the same conditions as the winding crown usually secured to the corresponding stem portion. If tube 15 has, on the contrary, been injured, nozzle 12 will no longer encompass tube 15 in a tight manner. In other words the adjustment of bore 14 is conceived so as to reveal any defect of tube 15 due to wear or to any undue deformation of its outer surface. Since the tubes 15 of the watches put on the market have standardized diameters, the watchmaker need only have a set of nozzles 12 corresponding to the existing tubes.

A tube 16 identical to tube 15 is removably set in bore 13 of conduit 11 So as to form a watertight seal between the outer surface of the part of tube 13 set in the wall of conduit 11 and this wall. Tube 16 has an outer surface 17 which has a diameter equal to the nominal diameter of the corresponding surface of tube 15. Tube 16 is provided for receiving the winding crown 18 of the watch. If the sealing gasket 19 of this crown is intact, it establishes a tight Seal around tube 16 exactly under the same conditions as if crown 18 were in its usual working position on tube 15. On the contrary, the seal between tube 16 and crown 18 will leak if gasket 19 is defective.

In the embodiment described the apparatus represented is intended for checking the tightness of a watch having a winding and hand-setting stem in two pieces. The stems of this type are well known to those skilled in the art. They comprise an inner part which is mounted in the watch movement and an outer part 20 which is secured to the crown 18. Part 20 is slit and it encompasses a male member of the inner part of the stem thus ensuring clutching of both stem parts. These stern parts can be removed from each other by merely pulling crown 18 somewhat stronger than as required for shifting it from winding into setting position.

To check a watch by means of the apparatus described its crown is first removed. Tube 15 of the watchcase is then introduced into bore 14 of nozzle 12 and blade 5 is located on such a pair of pins 6 that it strongly presses watch 4 against nozzle 12. Crown 18 together with part 20 of the winding stem is set on tube 16. These operations are, of course, carried out while container 1 is standing.

During these preparing operations piston 8 is at rest in its lower position, in which it is held by spring 10' being already compressed in this position.

After having set the watch and its crown in the described manner in the apparatus described piston 8 is pulled upwards as far as possible. This upward stroke of piston 8 does not reduce the pressure within the casing of watch 4. The sealing gasket of piston 8 is soft enough to allow an air flow from the cylinder section situated above piston 8 toward the lower cylinder section.

Button 9 is immediately released after it has been pulled upwards. Spring 10 thus moves piston 8 downwards. During this second stroke, the sealing gasket of the piston strongly bears against the inner surface of cylinder 7, thus producing a tight seal therewith.

The strength of spring 10 is chosen so as to produce an overpressure ranging about 1 atmosphere within the casing of watch 4. If this casing and crown 18 are tight. piston 8 will stop before returning into its rest position. Piston 8 can thus, for instance, remain in the position represented in FIG. 1.

To enable the downward stroke of piston 8 within cylinder 7, a small window 21 is provided in cover 22 of the pump.

If either the casing of watch 4 or the crown 18 has an important defect as regards the tight closure of the watchcase, piston 8 does not remain in the position represented in the drawing. It moves, on the contrary, downwards more or less quickly under the action of spring 10. This motion of piston 8 and button 9 rigidly connected therewith, will immediately reveal the presence of a strong tightness defect.

If, on the contrary, no displacement of piston 8 and button 9 can be observed in the position represented in FIGS. 1 and 2, the tightness of the casing and of the crown can only have small defects, so that the watch can be immersed without exposing its movement to liquid infiltrations.

While leaving piston 8 in the position represented, container 1 is laid down. As a consequence of that oper ation, watch 4 is immersed as shown in FIG. 3. The periphery of the watchcase and the crown can then quietly be observed in order to check whether air bubbles appear or not.

Using a liquid having less viscosity than water has the advantage to render the air bubbles even more quickly visible if there is some tightness defect. With such a liquid, the air ibubbles are, of course, smaller than with water so that-they flow more quickly.

If no bubble appears around the watch movement and the crown, watch 4 is perfectly tight. The apparatus can be returned into its standing position and the remaining drops of liquid can be blown away from tube 15 and crown 18. The watch and its crown can be removed from the apparatus and dried; finally, the crown can again be set in place on tube 15.

The overpressure produced within the casing of the watch could, of course, be generated by similar means and in the same way through another passage of the casing.

The strong tightness defects, which do not allow the watch to be immersed, could, of course, also be detected by means of a manometer instead of by observing the motion of a pump piston.

The open container 1 permits the tightness of a watch to be checked even if a wristband 23 is welded to its casing This wrist-band may indeed freely extend in front of container 1.

While one embodiment of the invention has been described in detail with reference to the accompanying, drawing, it will be understood that various changes in the shape, sizes and arrangement of parts will appear obvious to those skilled in the art without departing from the spirit of the invention or sacrificing the advantages thereof.

What is claimed is:

1. A method of testing the tightness of a watchcase comprising the steps:

first, establishing between the watchcase and a pump with a cylinder and a reciprocable and spring-loaded piston therein such a pneumatic connection that the watchcase inner space and the pump cylinder are communicating and constitute together a single space having always an equalized pressure in every point,

6 the piston thereby occupying in the pump cylinder its innermost pressed position in which it is normally held by the spring associated therewith;

second, increasing the volume of said single space while leaving its pressure substantially unchanged by merely pulling the pump piston against the action of the spring associated therewith;

third, increasing the pressure within said single space by simply abandoning the piston to the action of the spring associated therewith;

fourth, checking the position of the piston relative to the pump cylinder, and

fifth, if the piston remains at a standstill in an interme diate position along the pump cylinder, immersing the watchcase in a liquid exposed to the atmospheric pressure.

2. In the method of claim 1, the pressure increase produced within said single space being approximately equal to one atmosphere.

3. An apparatus for checking the tightness of a watchcase, comprising a support, resilient clamping means provided on said support, and a pump carried by said support and including a cylinder rigidly secured to said support, an outlet tube carried by said cylinder and having an inner end communicating with the cylinder inner space and an outer end arranged for providing a tight engagement of a passage across the wall of the watchcase, a reciprocable piston located within said cylinder, a gasket carried by said piston and engaging the cylinder, on the one hand, so as to allow air to pass by the piston when the latter is moved away of said outlet tube, and on the other hand, so as to prevent substantially any leakage between said cylinder and said piston when the latter is moved toward said outlet tube, and spring means acting on said piston and urging it toward said outlet tube, said clamping means being located at such a distance from the outer end of said outlet tube as to be able to press the watchcase thereagainst for safely holding it on said support.

4. In the apparatus of claim 3, said outlet tube being provided with a side bore extending across its wall, a tube having the same sizes as the watchcase tube provided for the winding stem being inserted in said bore and adapted for receiving the watch crown.

References Cited UNITED STATES PATENTS 1,042,558 10/1912 Karp 7345.5 2,054,204 9/1936 McDonald 7345.5 2,316,842. 4/ 1943 Coleman 73-455 2,697,935 12/1954 Gordon 7345.5 2,847,851 8/ 1958 Enell.

3,323,351 6/1967 Helms 73-45.5 3,355,932 12/1967 Mulligan 73-493 3,418,845 12/1968 Helms 73-455 S. CLEMENT SWISHER, Primary Examiner H. C. POST III, Assistant Examiner US. Cl. X.IR. 73-493 

